See image — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

# Finding Primary Alcohols of $C_5H_{11}OH$ **Step 1: Identify possible carbon skeletons** For $C_5H_{11}OH$, we need 5-carbon skeletons: - Linear: $CH_3CH_2CH_2CH_2CH_2-$ (n-pentyl) - Branched: $CH_3CH(CH_3)CH_2CH_2-$ (isopentyl) - Branched: $CH_3CH_2CH(CH_3)CH_2-$ (neopentyl) **Step 2: Determine primary alcohol positions** A primary alcohol has $-OH$ attached to a carbon bearing only one other carbon (or at a terminal position). **For each skeleton:** 1. **n-Pentane**: $-OH$ at terminal carbon → **$CH_3CH_2CH_2CH_2CH_2OH$** ✓ (1 isomer) 2. **Isopentane** ($CH_3CH(CH_3)CH_2CH_2-$): $-OH$ at terminal carbons: - → **$CH_3CH(CH_3)CH_2CH_2OH$** ✓ (2 isomers, but equivalent by symmetry = 1 unique) 3. **Neopentane** ($CH_3CH_2CH(CH_3)CH_2-$): $-OH$ at terminal carbon: - → **$CH_3CH_2CH(CH_3)CH_2OH$** ✓ (1 isomer) 4. **Methylbutane**: $-OH$ on secondary/tertiary carbons → ✗ (not primary) **Step 3: Count total primary alcohol isomers** - n-pentyl alcohol: 1 - isopentyl alcohol: 1 - neopentyl alcohol: 1 - 3-methylbut-1-ol: 1 **Total = 4 isomers** **Answer: (3) 4**